View Full Version : 1994 4l60E 1 2 upshift problem. No 2nd gear??
06-18-2011, 09:48 AM
I'm working on a 94 1/2 ton 4x4 Chevy truck with 4l60E having a few problems.
It wont up shift out of first gear unless I let completely off the gas.
If I let off the gas it will up shift but if you get back on the gas to much it will down shift back to first. If you just feather the gas to get it up to speed all is good. Also It dose not appear that the torque converter is locking up, but it is in over drive at 65 mph.
I am not sure if 2 gear is working or not. (I think its not)
Will test tomorrow in manual 2 to see what happens.
Any suggestions on what to look for before pulling the trans out?
06-18-2011, 01:53 PM
1-2 shift does not happen at WOT until you let off the gas: Best case: test the TPS for smooth linear response. Middle case: leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator).
Doublecheck by using the pressure gauge and watch for a big drop when the PCM commands 2nd gear. Worst case: poor line pressure rise
3. 1-2 Shift shudder at WOT; delayed or abnormal 1-2 shift; There's a problem ONLY on the 1-2 shift: 1-2 accumulator piston cracked or stuck ****ed in the bore.
Check the yellow spring inside the accum housing for breakage. Also, if the accumulator housing walls are scored, the housing must be replaced. Easy fix in the pan.
4. 1-2 shift is delayed and harsh, may not shift into OD: Check TPS for smooth and linear electrical response over the entire range of motion.
06-18-2011, 02:14 PM
I checked the tps and swaped it with another just to make sure then I drove it again this morning.
I realized by manually shifting it that 2 and 4th gears are gone. Just got done pulling the trans and inspecting it.
The 2 4 band is bad, the 2 gear accumulator was froze in the boar. and the drum that the band rides on is shoot.
I pulled and inspected the clutches and they look good almost new. So I am planning on just fixing the drum, band, 2 4 servo, sun shell (beast), and 2nd gear accumulator.
Any thing else I should look at well its out? should I drop the valve body and take a look?
06-18-2011, 02:18 PM
are you sure it is not going straight to 3rd when you let off? if so tranny rebuild may be in order
06-18-2011, 02:39 PM
when its supposed to be in 2nd gear its not its in 1st and when it supposed to be in 4th its in 3rd.
This was due to the band being toasted.
But what causes the band to burn up? It never was used to tow much at all.
Upgrade the 3-4 clutch pack to an 8 clutch Borg Warner Hi-Energy setup. And I would add the modified Heavy Duty TransGo Shift kit with Corvette servo that I offer. This will help all the gear shifts. Make sure you have an external transmission cooler. These things will add life and durability to the transmission. If you have any questions on this, let me know? Dana
06-19-2011, 12:28 PM
pm me a price for all that I need. I want for sure the following;
reverse input drum
2 4 band
pump gasket (both)
filter and pan gasket
2 pin less accumulators and housing
beast sun shell
Separator plate with "upgraded check balls"
How much extra for a full rebuild kit with proper clutches?
How much extra for the 2 cage sprags?
How much more for transgo kit?
I am thinking about leaveing the clutches alone for now they all looked very good.
06-19-2011, 03:00 PM
Is it normal for the 4th gear accumulator to have no spring in it??
06-20-2011, 10:09 AM
go to probuilt automatics(PBA) online for pricing on rebuild kits.
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